The electromagnetic spectrum ranges from cosmic rays at one end, to radio waves at the other end. The ultraviolet (UV) region of the electromagnetic spectrum is situated between visible light and x-rays, with the wavelengths of the UV A radiation being shorter and more energetic than violet visible light and the wavelengths of vacuum UV radiation being slightly longer and less energetic than x-rays. The full UV radiation spectrum ranges from wavelengths of about 100 nanometers (nm) to 400 nanometers and the UV radiation spectrum is usually divided into 4 sections; vacuum UV radiation (also called far or very UV, from 100 nm to about 200 nm), UV C radiation (also called germicide or short-wave UV, from 200 to about 280 nm), UV B radiation (also called mid-wave or medium-wave UV, from 280 nm to about 320 nm), and UV A radiation (also called “poster lamp”, black-light, or long-wave UV, from 320 nm to 400 nm).
UV radiation can be emitted from a variety of sources such as light emitting diodes (LED's), lasers, electric arcs (especially as in arc welding), xenon bulbs, halogen bulbs, excimer bulbs, and mercury vapor lamps/tubes of low, medium and high pressures. UV C radiation is used extensively for sterilization, purifying, and deodorizing applications in food, air, water, and general surface sterilization processes because the UV C radiation not only deactivates micro-organisms such as: bacteria, molds, spores, fungi, and viruses (by direct irradiation which damages the DNA such that the micro-organisms cannot reproduce), but the UV C radiation also breaks down the chemical bonds of alcohols, pesticides, chloramines, and other contaminants such as NDMA or MTBE. UV B radiation is the agent that causes human skin to “sun-burn” and the UV B radiation is needed to start the suntanning process. The lamps/tubes used in suntanning booths usually emit a combination of UV B and UV A. UV B is also used extensively in various medical treatments—especially for skin diseases. UV A radiation is used for special effect lighting, suntanning, photo-lithotropy, and photo-chemistry.
U.S. Pat. No. 6,787,782 teaches a system that uses UV radiation emitting LED's as one source of UV radiation for sterilizing air in a vehicle such as an airplane. Similarly, U.S. Pat. No. 6,233,748 teaches the use of UV radiation emitting LED's in combination with a reactive surface to sterilize air for breathing inside a helmet. Neither of these two Patents teaches any way to vary or transform the radiation from the UV radiation source.
In U.S. Pat. No. 5,736,744; U.S. Pat. No. 6,670,619; and U.S. Pat. No. 6,911,657, inventor Waluszko describes a wavelength shifting filter as only emitting one particular wavelength distribution of radiation. Waluszko does not teach the use of conversion plates with LED's.
The present invention relates to ultraviolet radiation (UV) emitting devices used in the fields of mineralogy; scientific research; forensics; UV sterilization of food, water, air, fluids, and surfaces; area illumination; photo-chemistry, photo-medical treatments, photo-lithography, artistic displays of fluorescent materials; and similarly related fields. Specifically, the present invention provides a method and device whereby the primary wavelength distribution of radiation being emitted from a primary UV radiation source such as a UV Light Emitting Diode (LED) may be transformed into a secondary wavelength distribution of radiation that is different from the primary wavelength distribution of radiation, and wherein the device comprises a small form factor device, of an LED flashlight type design, suited for carrying in a pocket, or by the hand, and whereby field use of the UV emitting device is very easy and efficient.